A Comprehensive Study on Reinforced Concrete Building at Different Seismic Zones In Bangladesh

Abstract

This thesis examines the seismic performance and cost implications of a low-rise garment factory (150 x 72 ft, 79 ft tall) across all four seismic zones defined by BNBC-2020, using ETABS-21 for structural analysis. In the absence of shear walls, Zone 4 demonstrates the highest seismic vulnerability, with a maximum storey displacement of 3.5 inches at the rooftop and a peak drift of 0.015hx between the second and third floors. These results underscore the necessity for high-strength steel (compressive strength >40 MPa, tensile strength >60 ksi) and flexible or hybrid structural systems to ensure stability and safety in this high-risk zone. For Zones 1–3, a 1.5–2.5% reinforcement rate is adequate to maintain structural integrity, assuming stable interest rates. The analysis indicates that base shear values from ETABS-21 are 5–15% lower than those derived from BNBC-2020, highlighting the need for additional verification to meet safety standards. In Zone 2, elevated rebar demand promotes the use of larger columns (16" x 16"), which can reduce material costs by up to 15%, enhancing cost efficiency. The study emphasizes the unique seismic challenges faced by Bangladesh’s garment industry, a vital economic pillar, necessitating advanced construction techniques and modern earthquake- resistant technologies. By integrating high-strength materials and optimized structural designs, the research advocates for safer, more cost-effective, and sustainable building practices. These findings are critical for ensuring the durability and resilience of industrial structures in seismically active regions while complying with BNBC-2020 standards. The thesis strongly supports zone-specific design strategies to address varying seismic risks, promoting innovative engineering solutions that balance safety, efficiency, and sustainability. This approach is essential for supporting Bangladesh’s infrastructure development and economic stability, particularly in the garment sector, which faces significant environmental challenges. By adopting these advanced methods, the industry can achieve long-term resilience, ensuring both worker safety and economic viability in the face of seismic hazards, thereby contributing to the nation’s sustainable growth and development.